a. Field of the Invention
This invention relates to a power transmission device for wheels to be driven in motor vehicles such as motorcycle, automobiles, and so forth. More particularly, it is concerned with a device for preventing the drive shaft from being overloaded, thereby attaining equalized distribution in weight to be imposed on the drive shaft.
B. Description of Prior Art
It has been deemed necessary to provide on the propeller or drive shaft in the power transmission device for such motor vehicles a buffer device for preventing the propeller shaft from becoming overloaded so as to relax excessive impact force to be imposed on the power transmission mechanism at the time of speed changing, abrupt braking operation, and so forth.
In the case of a motorcycle driven by a drive shaft, or an automobile of a front-engine-rear-drive type, however, when such buffer device is provided in the intermediate portion of the propeller shaft in view of the length of the shaft, there would occur an inconvenience such that, as the buffer device is of a considerable weight, distribution of weight on the propeller shaft becomes difficult, and, further, the shaft is subjected to flexure due to centrifugal action accompanied by the shaft rotation. Moreover, an additional space is required around the propeller shaft for fitting the buffer device, which constitutes an obstacle against the desired compact design of the vehicle body.